import { app } from './init'
import {
  getFirestore,
  doc,
  setDoc,
  getDoc,
  onSnapshot,
  collection,
  query,
  where,
  limit,
  getDocs,
} from 'firebase/firestore'
import { getAuth } from 'firebase/auth'
import { ref, getStorage, uploadBytes, getDownloadURL } from 'firebase/storage'
import {
  onAuthStateChanged,
  GoogleAuthProvider,
  signInWithPopup,
} from 'firebase/auth'

export const STARTING_BALANCE = 100

export type User = {
  id: string
  email: string
  name: string
  username: string
  avatarUrl: string
  balance: number
  createdTime: number
  lastUpdatedTime: number
}

const db = getFirestore(app)
export const auth = getAuth(app)

export async function getUser(userId: string) {
  const docSnap = await getDoc(doc(db, 'users', userId))
  return docSnap.data() as User
}

export async function getUserByUsername(username: string) {
  // Find a user whose username matches the given username, or null if no such user exists.
  const userCollection = collection(db, 'users')
  const q = query(userCollection, where('username', '==', username), limit(1))
  const docs = await getDocs(q)
  const users = docs.docs.map((doc) => doc.data() as User)
  return users[0] || null
}

export async function setUser(userId: string, user: User) {
  await setDoc(doc(db, 'users', userId), user)
}

export function listenForUser(userId: string, setUser: (user: User) => void) {
  const userRef = doc(db, 'users', userId)
  return onSnapshot(userRef, (userSnap) => {
    setUser(userSnap.data() as User)
  })
}

const CACHED_USER_KEY = 'CACHED_USER_KEY'
export function listenForLogin(onUser: (_user: User | null) => void) {
  return onAuthStateChanged(auth, async (user) => {
    if (user) {
      let fetchedUser = await getUser(user.uid)
      if (!fetchedUser) {
        // User just created an account; save them to our database.
        fetchedUser = {
          id: user.uid,
          name: user.displayName || 'Default Name',
          username: user.displayName?.replace(/\s+/g, '') || 'DefaultUsername',
          avatarUrl: user.photoURL || '',
          email: user.email || 'default@blah.com',
          balance: STARTING_BALANCE,
          // TODO: use Firestore timestamp?
          createdTime: Date.now(),
          lastUpdatedTime: Date.now(),
        }
        await setUser(user.uid, fetchedUser)
      }
      onUser(fetchedUser)

      // Persist to local storage, to reduce login blink next time.
      // Note: Cap on localStorage size is ~5mb
      localStorage.setItem(CACHED_USER_KEY, JSON.stringify(fetchedUser))
    } else {
      // User logged out; reset to null
      onUser(null)
      localStorage.removeItem(CACHED_USER_KEY)
    }
  })
}

export function getCachedUser() {
  if (typeof window !== 'undefined') {
    const cachedUser = localStorage.getItem(CACHED_USER_KEY)
    return cachedUser ? (JSON.parse(cachedUser) as User) : undefined
  }
}

export async function firebaseLogin() {
  const provider = new GoogleAuthProvider()
  signInWithPopup(auth, provider)
}

export async function firebaseLogout() {
  auth.signOut()
}

const storage = getStorage(app)
// Example: uploadData('avatars/ajfi8iejsf.png', data)
export async function uploadData(
  path: string,
  data: ArrayBuffer | Blob | Uint8Array
) {
  const uploadRef = ref(storage, path)
  // Uploaded files should be cached for 1 day, then revalidated
  // See https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cache-Control
  const metadata = { cacheControl: 'public, max-age=86400, must-revalidate' }
  await uploadBytes(uploadRef, data, metadata)
  return await getDownloadURL(uploadRef)
}